Cheapest return flights from St. Louis to Denver in December from $80

AirHint found the following cheapest return flights from St. Louis (STL) to Denver (DEN) in December 2025 (see full year).

Return flights

13 Dec - 17 Dec Frontier Airlines direct
17 Dec - 24 Dec Frontier Airlines direct
12 Dec - 10 Jan Frontier Airlines
12 Dec - 12 Jan Frontier Airlines
20 Dec - 27 Dec Frontier Airlines direct
21 Dec - 28 Dec Frontier Airlines
22 Dec - 28 Dec Frontier Airlines
23 Dec - 28 Dec Frontier Airlines
31 Dec - 06 Jan Frontier Airlines
22 Dec - 26 Dec Frontier Airlines
24 Dec - 03 Jan Frontier Airlines direct
23 Dec - 03 Jan Frontier Airlines
31 Dec - 03 Jan Frontier Airlines direct
30 Dec - 02 Jan Frontier Airlines
25 Dec - 03 Jan Frontier Airlines
31 Dec - 06 Jan United direct
14 Dec - 21 Dec Frontier Airlines
05 Dec - 06 Dec Frontier Airlines
06 Dec - 07 Dec Frontier Airlines
27 Dec - 02 Jan Frontier Airlines direct

Also check the deals for one-way flights from St. Louis to Denver in December.

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